The present invention is an improved flexible rotor valve seal and an improved ganged rotor valve utilizing the seal.
More particularly, this invention is an improvement of the seal disclosed in Flexible Seal for Rotor Valves, U.S. Pat. No. 4,548,385, Oct. 22, 1985, by one of the present inventors. The improved seal permits the manufacture of a novel ganged multiway rotor valve, e.g. an 8-way value.
The rotor valve seal of U.S. Pat. No. 4,548,385 works excellently in the usual applications for which it was designed. However, when the valve has an extended rotor and a multiplicity of ports, the seal of the patent provides such a large contact area that rotor movement is unduly stiff or impeded requiring undue force to turn the rotor or a larger drive motor than may be necessary. Also, because the plastic of the seal expands with heating, it is desirable to reduce the mass thereof as much as possible. In addition, the expansion of the seal material upon heating also leads to, or adds to, stiff or impeded rotor movement.
The seal of the patent is characterized by having a rectangular shape that fits or slides into a flat-bottomed channel in the valve rotor that lies about the port to be sealed. In a 4-way valve with the ports spaced 90 degrees about the rotor, 4 such seals would be used each having an opening registering with the ports of the rotor and valve body. The outer surface of the seal is curvilinear, mating with the curvature of the valve body. As is shown in the patent, the inner flat surface of the seal mates with the flat bottom of the channel in the rotor and has a circular groove about the port to be sealed which groove retains an O-ring. The rectangular shape of the seal works well, but with the particular design of the seal device, a better seal is achieved with increased internal pressure within the valve. While increased pressure provides for a better seal, it also leads to increasingly stiff action of the valve requiring increasing force to turn the rotor. In addition, the rectangular shape of the seal includes comers which can be collection points for particulate contaminants, also leading to an increase in the force or torque required to turn the rotor and operate the valve.
Thus it would be desirable to have a rotor valve seal and valve with reduced thermal expansion of the components within the valve, reduced potential collection points for contaminants, and a seal mechanism that does not require increased internal pressure to provide a tighter seal. It would be desirable to have a rotor valve seal and valve that would always be operable with low amounts of torque regardless of temperature, pressure within the valve and contaminants.